1. Field of the Invention
The invention relates to a control device for semiautomatic gearshift mechanisms of vehicles, in particular, motor vehicles, comprising two actuators with which the gearshift shaft of the gearshift mechanism is rotatable and movable (slidable) for gutter selection and gear selection.
2. Description of the Related Art
In connection with manual gearshift mechanism it is known to select the desired gutter and gears with a gearshift lever projecting into the passenger compartment. In order to provide an automatic operation of such a manual gearshift mechanism, control devices with actuators are known with which the gearshift shaft of the gearshift mechanism is rotated and moved.
It is an object of the present invention to configure the control device of the aforementioned kind such that with a compact and inexpensive configuration a problem-free and reliable gearshift action is ensured.
In accordance with the present invention, this is achieved in that the first actuator for sliding or moving the gearshift shaft has a primary piston having correlated therewith at least two auxiliary pistons with which the primary piston can be moved in two directions, as desired, and that the primary piston has two piston rods extending in the travel direction and projecting from opposite sides of a piston body of the primary piston.
In the control device according to the invention, the gearshift shaft of the gearshift mechanism is moved by means of the primary piston in cooperation with the auxiliary pistons. For this purpose, the auxiliary pistons as well as the piston rods of the primary piston are correspondingly loaded, preferably by means of a hydraulic medium. By employing two auxiliary pistons and two piston rods, the primary piston can be adjusted into a position corresponding to the respective gearshift mechanism. The actuator can be used for movement (displacement) or rotation of the gearshift shaft. It is also possible to provide both actuators with such a primary piston with piston rods and with auxiliary pistons. Then it is possible to employ the same units for both actuators of the control device according to the invention.